Author's Note: I've been enjoying reading everyone's theories about Sunglasses and who she really is. Rest assured, by the end of this story, you'll have your answer.

(Sometimes, my readers have theories that are better than what I came up with. Then, I tend to run off and write stories about their theories!)

As you'll see in this next section, there's a good reason why the PTB got so confused between River Song and Seo.

Enjoy!

(By the way, to respond to "Guest", I've actually never seen that show. I brainstormed Sunglasses' speech during a really boring drash the rabbi delivered during High Holidays. If you're not Jewish, I'll clarify; High Holidays are one of the few times when everyone's at Synagogue, so it's when rabbis all get up and try to guilt you into giving more money to the synagogue. Usually, they have the first drash, which is actually interesting and fun to follow, and then they move on to the boring speeches about giving money, and I zone out. This time, I started writing, in my head, bits of dialogue for Sunglasses.

Incidentally, this is the only time I can think of when having a spiritual leader designed to make you forget what they said might actually make sense. Confessors, indeed! Psha!)

"—closely, you'll see the same thing happening again," came a voice.

Seo stared. She'd just come to, to find herself chained up and facing down two people wearing eye patches. A man and a woman.

Mr. and Mrs. Eye Patch, she decided to nickname them.

What was this? Dress-Like-A-Pirate Day? Or was this some sort of branding thing their marketing department had put together, to make them seem more 'evil'?

Well. Hard for a group whose sole purpose was to kill the Doctor to be more evil…

Wait a sec.

"Dawn," Seo remembered. Suddenly recalling what had happened just before she'd come to. The chase and the capture. Seo struggled to free herself. "Where is she? What did you do with her? If you've hurt her in any way…!"

"She's still looking right at it," Mrs. Eye Patch told her associate. "She never stopped. All that changed was the visible spectrum of light in the room. We flipped the light switch. And it completely erased her short-term memory."

"She must still be registering them, somehow," Mr. Eye Patch hypothesized. "Somewhere deep in her subconscious." He turned to the woman. "That might enhance her susceptibility to hypnotic suggestion, if they give her commands."

"It has," Mrs. Eye Patch replied. "She's already done things for us that she'd never normally dream of doing."

Seo felt a deep chill run through her.

Didn't know what they were talking about. And was scared to find out.

"You've… you've been altering my memory?" Seo asked. "You've been…?"

"She won't kill him, though," Mrs. Eye Patch told her comrade, ignoring Seo completely. "It was the first conditioning we tried."

"Shame."

"Yes," Mrs. Eye Patch agreed. "We can't work out why. As far as we can see, she'll hurt him. Beat him to within an inch of his life, if we give her enough persuasion. Have the poison of the Judas Tree in her hands, ready to deliver. But she'll never actually take that final step."

Mr. Eye Patch tapped his chin, thoughtfully.

"The current theory is she's been conditioned from birth not to," Mrs. Eye Patch provided.

"That in itself is interesting," Mr. Eye Patch replied. "If we could get someone like her — who's conditioned, from birth, the opposite way…"

Seo's left chain was loose.

Seo managed to pull it from the wall. Then yanked the chain around so that the metal end slammed against Mr. Eye Patch's arm, causing him to jump back, with a sharp cry. Seo kept yanking on the other chain. She knew she could pull it free.

"What—?" Mr. Eye Patch said, rubbing his arm.

"I don't like people who mess with kids," Seo growled at him.

Mrs. Eye Patch didn't seem concerned. "She's perfectly harmless," she said. Put her hands out into the air, and then moved them to the side. "Just move the creature out of her line of vision…"

"And she'll forget…?" Mr. Eye Patch said.

Seo darted her eyes over to look straight at him.

And forgot.

Leah lit some candles, in her apartment. The whole city blacked out around her. The woman, meanwhile, just sat down in one of the armchairs, making herself comfortable.

"Look, even if I did know who this… Dawn person is," said Leah, striking a match, "which I don't — why do these things want her?"

"Not things," said the woman. "Silents. They're called the Silents."

Leah lit the candle. Shook out her match. "Yeah. Silence. Because no mouths. Funny."

"No mouths?" said the woman. She thought this over. "Interesting."

Leah glared at the woman. "Look, do you want something? Or are you just going to sit there making cryptic comments?"

The woman put her hands on her knees. "Describe the Silents."

So… yeah. Looks like whoever-this-was was just in it for the cryptic comments.

Great.

"You saw the creature, too," said Leah. "You tell me."

"I'd rather hear your impression."

Leah sighed. Why did she indulge nutcases like this? "Tall. Slim. Wearing a suit and tie. Massive bone structure around the face. No mouth — like I said before. And…" She stopped, as she noticed the grin on the other woman's face. "What?"

The woman grinned even wider.

Leah felt even less comfortable than before. "What? I mean… they do look like that, right? Or is this your sick idea of a practical joke?"

"I don't know what the Silents look like," the woman confessed. "No one does. Nobody else can remember them."

Leah paused.

Frowned. "Wait, what?"

"The Silents are memory-proof," the woman explained. "While you're looking at them, you can remember. But the moment you look away, you forget. See them again, and everything comes flooding back. But only while they're in your sight."

Leah stared. "That's impossible. I mean, I remember them."

The woman raised her eyebrows.

And Leah sunk back on the couch. As it all made sense. "That's why you're interested in me."

"One of the reasons, yes," the woman agreed. She folded her hands in her lap. "I don't want them to know about your little… ability."

Leah's head was spinning. "But… but if no one else can remember these guys," she said, "then why do you? I mean, you stepped right out in front of that other one, and you still remember that!"

"Well, I did come prepared." The woman swept the sunglasses off her head, looked down fondly at them. "Never let me down, yet."

Oh. Right.

Leah had been wondering why the woman had been wearing sunglasses at night.

"So… they're some sort of memory-reinforcing sunglasses?" Leah guessed. "Something to make you able to see and recall those things, even when…?"

The woman laughed.

Tossed the sunglasses over to Leah.

Leah caught them. Examined them, carefully. Then, a little hesitantly, put them on. And could see absolutely nothing.

Pitch black.

"I switched them into blackout mode," the woman said. "The Silents wipe your memory based on whether or not you can see them. With these glasses, I can't see anything at all."

"You didn't act blind, when you wore them."

"I've learned some visualization techniques, over the years," said the woman. "I don't necessarily need to be able to see something in order to understand how it'll look." She shrugged. "Takes a lot of concentration, though."

Leah slid the glasses off her face. "You should get yourself an army of blind people," she muttered, handing them back. "They'd wipe these Silence things out in no time."

The woman took back the glasses, and propped them back up on her head, pushing back her hair. "There are only two people in the universe who naturally react in a different way towards the Silents," she said. "You. And one other — someone you've met."

Leah frowned.

And then it came back to her.

That blond girl, staring straight ahead of her — right at one of the creatures — and shouting, "I am looking! But there's nothing there!"

A blond girl.

Named…

"Seo," Leah breathed. "She couldn't see those Silence creatures at all. Not even when she was staring right at them."

"That's right."

"Except… with her… that didn't make things better," Leah recalled. "It made the amnesia even worse."

Madame Kovarian raised an eyebrow at Dr. Pandol, who was still studying the readouts from the machinery. "Conclusions?"

"It's fascinating," said Pandol. He glanced back at Kovarian. "How did you find machinery that would read her? I've tried numerous times, but nothing picks her up."

"I didn't find it," said Kovarian. "She built it for us."

Pandol nodded, with a small grin. "Hypnotic suggestion?"

"I told you she was more susceptible to it than others," said Kovarian. "She'll do almost anything. Tell us almost anything." She gestured at the readouts. "Notice how she's put together?"

Pandol squinted. "Looks a bit like… his physiology."

"Except she was created by human beings," said Kovarian. "On Earth. As a weapon."

Pandol turned. Stared at her. "I'm sorry?"

"Her exact words were 'a weapon to take down gods'," said Kovarian. She folded her arms. "Which sounds a little like what we're trying to do. Take down a man who thinks himself a god."

"Remarkable," said Pandol, returning to the readings. He shook his head. "Shame she won't kill him."

"Or an opportunity," said Kovarian.

"Opportunity?"

"Reverse engineering," said Kovarian. "We were already planning to create our own little assassin. If we find out how she was made — imagine how much more powerful our assassin could be."

Pandol nodded, slowly. "Because of the super strength."

"And the rest," said Kovarian. "She says she popped into existence, from nowhere. Energy turned into matter. The memories of everyone around her were rewritten." Kovarian smiled. "Imagine if we could do that with the Doctor."

"Create a fake companion," Pandol continued, "who'll pop into existence right in his TARDIS. Whom he won't remember shouldn't be there."

"He'll trust her," said Kovarian, "right up until the moment he dies for good."

"Brilliant."

Pandol waited for Kovarian to continue. Explain how they'd go about it.

But she didn't.

"We… did obtain an account of how she was created, right?" Pandol checked.

Kovarian sighed. "No," she admitted. "She doesn't know the details. And even the most sophisticated techniques we have can't work it out. Not with Seo." She paused. Then corrected, "Not with only Seo."

Pandol tried to think it through. "The one she keeps talking about," he recalled. "Her… Aunt Dawn. You think she could help?" He shook his head. "But what help would a normal human be, if we want to discover…?"

Kovarian turned to the door. "I think, Dr. Pandol," she said, "you should read the Slayer Institute's ancient legends. Then draw your own conclusions about 'Dawn'."